The following article relates to 2G, 3G and 4G LTE:
What is a reasonable Signal Strength?
For general guide in NB IoT:
- Strong: RSRP ≥ -100 dbm, and RSRQ ≥ -7 dB
- Median: -100 dbm ≥ RSRP ≥ -110 dbm, and -7dB ≥ RSRQ ≥ -11 dB
- Weak: RSRP < -115 dbm, or RSRQ < -11 dBb
In LTE (includes CAT.M1 and NB IoT) signal strength/quality parameters: RSRP, RSRQ, RSSI, SINR and their meaning.
Scholarly white paper on the extra 21dBm advantage CAT.M1 (LTE-M) has over 4G LTE:
Coverage Enhancement modes:
•CE Mode A: A maximum of UL/DL 32 Repetitions with QPSK, supported by all LPWA platforms. Within this mode there is ECL0 (no repetitions), ECL1, ECL2 (Max. repetitions).
•CE Mode B: A maximum of UL/DL 2048 Repetitions, optional not supported by current Quectel LPWA platforms. Note that such a large number of repetitions would mean minutes of peak current transmit, and impact battery life significantly.